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MASS
ISSUE NO. 1
ERIC HELMS | GREG NUCKOLS | MICHAEL ZOURDOS
APRIL 2017
MONTHLY APPLICATIONS IN
STRENGTH SPORT
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Letter from the Reviewers
WELCOME to the first issue of Monthly Applications in Strength Sport
(MASS)!
If you (or your clients) want to build muscle, get stronger, and/or drop fat as efficiently and effectively as possible, MASS is for you. Our focus is nar-rower than other research reviews, focusing solely on strength and physique athletes and coaches. This means that every month, we’ll review only the research that’s the most relevant for you and your results.
It’s important for athletes and coaches to be on top of the research, but we know that doing so is quite inefficient when flying solo. It takes a long time to sift through journals and find the studies that are relevant to you. It takes even longer to read and digest those studies, and it takes even longer yet to contextualize new research in the broader body of literature. That’s what MASS is for. We do all the heavy lifting for you and distill the most important findings into an easy-to-read monthly digest.
This first issue should give you an idea of what you can expect from MASS. We cover the relationship between muscle damage and muscle growth, whether the intensity of aerobic training affects the degree to which cardio interferes with strength and muscle gains, whether flexible training plans produce better results than rigid training plans, and much more. Each issue will tackle new questions, keeping you up to date with the current research, and giving you a thorough understanding of the best science-based practic-es. We hope you enjoy it, and we hope you’ll subscribe so you can stay on the cutting edge of our field to get the best results possible for yourself or your clients.
Thanks so much for reading.
The MASS Team
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The Reviewers
Eric Helms
Eric Helms is a coach, athlete, author, and educator. He is a coach for drug-free strength and physique competitors at all levels as a part of team 3D Muscle Jour-ney. Eric regularly publishes peer-reviewed articles in exercise science and nutrition journals on physique and strength sport, in addition to writing for commercial fitness publications. He’s taught undergraduate- and graduate-level nutrition and exercise science and speaks internationally at academic and commercial conferences. He has a B.S. in fitness and wellness, an M.S. in exercise science, a second Master's in sports nutrition, and is a strength and conditioning Ph.D. candidate at Auckland University of Technology in New Zealand. Eric earned pro status as a natural bodybuilder with the PNBA in 2011 and competes in the IPF at international-level events as an unequipped powerlifter.
Greg Nuckols
Greg Nuckols has over a decade of experience under the bar and a B.S. in exercise and sports science. Greg is currently enrolled in the exercise science M.A. program at the University of North Carolina at Chapel Hill. He’s held three all-time world records in powerlifting in the 220lb and 242lb classes. He’s trained hundreds of athletes and regular folks, both online and in-person. He’s written for many of the major magazines and websites in the fitness industry, including Men’s Health, Men’s Fitness, Muscle & Fitness, Bodybuilding.com, T-Nation, and Schwarzenegger.com. Furthermore, he’s had the opportunity to work with and learn from numerous record holders, champion athletes, and colle-giate and professional strength and conditioning coaches through his previous job as Chief Content Direc-tor for Juggernaut Training Systems and current full-time work on StrongerByScience.com.
Michael C. Zourdos
Michael (Mike) C. Zourdos, Ph.D, CSCS, is an assistant professor in exercise sci-ence at Florida Atlantic University (FAU) in Boca Raton, FL., USA, with a special-ization in strength and conditioning and skeletal muscle physiology. He earned his Ph.D. in exercise physiology from The Florida State University (FSU) in 2012 under the guidance of Dr. Jeong-Su Kim. Prior to attending FSU, Mike received his B.S. in exercise science from Marietta College and M.S. in applied health physiology from Salisbury University. Mike served as the head powerlifting coach of FSU’s 2011 and 2012 state championship teams. As an assistant professor at FAU, Mike is the direc-tor of the FAU Muscle Physiology Research Laboradirec-tory. He also competes as a powerlifter in the USAPL, and among his best competition lifts is a 230kg (507lbs) raw squat at a body weight of 76kg. Mike owns the company Training Revolution, LLC., where he has coached more than 100 lifters, including a USAPL open division national champion.
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Does the Configuration of Weekly Training Session Order Matterfor Strength?
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B Y M I C H A E L C . Z O U R D O SIs It Better to Combine Lifting With High Intensity or Traditional Cardio?
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B Y G R E G N U C K O L SIs Muscle Damage Related to Hypertrophy?
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B Y E R I C H E L M SWhen the Whole is Less Than the Sum of its Parts
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B Y G R E G N U C K O L STable of Contents
If you need to add cardio to your lifting, is it better to stick with high intensity intervals (which some have called "anabolic cardio"), or to opt for traditional moderate intensity cardio? This was the first study designed to actually answer that question.
When you give lifters some flexibility in their training, do they get better results? This study compared a rigid training program with a program that let the lifters order each training week as they saw fit. Did they get better results from "listening to their bodies?"
Lots of studies measure muscle protein synthesis (MPS), but don't check to see if increases in MPS actually equate to long-term muscle growth. This study set out to answer that question, while also showing that muscle damage muddies the water.
Single leg training has grown in popularity in recent years, largely due to theories based around the "bilateral deficit" phenomenon. What is the bilateral deficit, what causes it, and does it actually affect athletic performance or injury risk?
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More Volume is Not Always Better40
B Y M I C H A E L C . Z O U R D O SPushing it to the Limit: Gauging How Far We Are From Failure
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B Y E R I C H E L M SCan You Improve Your Lifting Technique By Intentionally Screwing Up?
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B Y G R E G N U C K O L SVIDEO: The Real Effects of Pre-Exercise Stretching
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B Y M I C H A E L C . Z O U R D O SVIDEO: Structuring Flexible Dieting, Part 1
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B Y E R I C H E L M SIf some is good, more is better, right? Maybe not. German Volume Training, a notoriously high-volume training approach, didn't fare so well compared to a training program with considerably less volume.
How accurately can lifters assess their level of effort? This study sought out to see just how good people were at telling how far they are from failure to see if rate of perceived exertion (RPE) is a valid way to prescribe training loads.
We've all heard that we're supposed to learn from our mistakes. What if you actually learn best by purposefully amplifying your mistakes? It sounds counterintuitive, but this study found that amplifying errors could improve snatch technique better than traditional instruction.
Static stretching before training is still far too common. This video breaks down the effects of static stretching on a physiological level, and shows you better options to get more out of your warm up.
Flexible dieting has grown in popularity over the past couple of years, but unfortunately, misinformation and myths about it have increased in prevalence as well. The first video in our series on flexible dieting digs into its background and tells you what flexible dieting really is.
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B Y G R E G N U C K O L S
Study Reviewed: Endurance training intensity does not
mediate interference to maximal lower-body strength gain
during short-term concurrent training. Fyfe et al. (2016)
oncurrent training is the simulta-neous inclusion of both resistance and endurance training within the same training program. Previous research (1) suggests that concurrent training leads
to somewhat smaller gains in strength and muscle mass than resistance training alone. However, to this point, no studies had com-pared concurrent training utilizing high in-tensity endurance training (intervals) versus
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Is It Better to Combine Lifting With
High Intensity or Traditional Cardio?
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moderate intensity endurance training.In this study, both concurrent training groups gained a similar amount of strength in the bench press and leg press, but less strength in the leg press than the group only performing strength training. Measures of explosive strength (peak force and peak power in the counter-movement jump) favored the group only performing resis-tance training, and unsurprisingly, measures of endurance (VO2 peak, and peak aero-bic power) favored the concurrent training groups. The concurrent training group do-ing moderate intensity endurance traindo-ing gained roughly the same amount of lower body lean mass compared to the group only performing resistance training, while the concurrent training group doing high in-tensity endurance training gained slightly less lower body lean mass.
Purpose and Research
Questions
Numerous studies have compared con-current training with resistance training. However, the endurance training aspect of concurrent training can take many forms, running the gamut from very low intensi-ty cardio to very high intensiintensi-ty intervals. To this point, no studies had directly compared concurrent training programs utilizing two different approaches to endurance training.
The authors hypothesized that high in-tensity endurance training (HIT) would compromise gains in strength more so than moderate intensity endurance train-ing (MOD), since HIT tends to be more fatiguing and lead to larger acute decreases in strength when compared to MOD with similar volumes. Alternately, various prom-inent writers and coaches have proposed
KEY POINTS
1. The interference effect describes the relatively smaller gains in strength and hypertrophy seen when combining strength and endurance training versus performing strength training in isolation.
2. This study set out to see whether high intensity intervals or moderate intensity steady state cardio interfered more with hypertrophy and strength gains when combined with strength training.
3. High and moderate intensity cardio interfered with strength gains and hypertrophy to a similar degree – the subjects made gains, but smaller gains than the folks only doing strength training.
4. When looking at both results and effort invested, moderate intensity cardio came out on top. The participants consistently rated high intensity interval training as consistently more challenging than moderate intensity cardio, even though time and workload were equated.
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that MOD will cause muscle atrophy andstrength losses, while HIT will help one build muscle and strength.
Subjects and Methods
The subjects were males, mostly 25-35 years old, who participated in some form of resistance or aerobic exercise at least twice per week.
At the outset of the study, they were DXA scanned, tested their 1RM bench press-es and leg prpress-esspress-es, took a graded exercise test on a cycle ergometer, and performed a counter-movement jump test. All of these tests were repeated at the end of the study, and the exercise tests were also performed again at the midpoint of the training
inter-vention.
The participants were assigned to one of three training programs: resistance train-ing only, resistance traintrain-ing plus HIT, and resistance training plus MOD. All groups carried out the same resistance training pro-gram three days per week, which utilized a basic linear periodization design, starting with 3 sets of 12 with 65% of 1RM, and progressing to 5 sets of 4 with 90% of 1RM over 8 weeks.
The endurance training was performed directly before the strength training (lift-ing started 10 minutes after the endurance training session finished). HIT and MOD were matched for both time and total train-ing volume. HIT consisted of cycltrain-ing inter-vals consisting of 2 minutes of high exertion
MON./FRI. PROGRAM: leg press, bench press, seated row, leg extension, and leg curl
WED. PROGRAM: leg press, DB bench press, lat pulldown, DB lunges, and leg curl
Sets × repetitions RM load
Rest period (min) % 1RM load 3×12 14 2 65 3×10 12 2 70 3×8 9 2 77.5 3×6 7 3 82.5 4×6 7 3 82.5 4×6 7 3 87.5 4×6 7 2 87.5 3×6 7 2 87.5 4×4 4 3 90 5×4 4 3 90 3×12 14 2 65 3×12 14 2 65 3×10 12 2 70 3×10 12 2 70 3×8 9 2 77.5 3×8 9 2 77.5
Week 1 Week 2 Week 3 Week 4 Week 5 Week 6 Week 7 Week 8
Sets × repetitions RM load
Rest period (min) % 1RM load
RM = repetition maximum | 1RM=one-repetition maximum
P R O G R E S S I O N O F R E S I S T A N C E
T R A I N I N G P R E S C R I P T I O N
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and 1 minute of rest. Volume and intensityincreased over the course of the study, from 5 intervals at 120% of lactate threshold (roughly 70-75% of VO2 peak) to a max of 11 intervals at 150% of lactate threshold (roughly 90% of VO2 peak). MOD consist-ed of steady-state cycling, starting with 15 minutes at 80% of lactate threshold (rough-ly 50% of VO2 peak) and peaking at 33 minutes at lactate threshold (roughly 60% of VO2 peak).
The researchers also monitored diet and per-session rating of perceived exertion.
Findings
Perceived difficulty
The participants gave HIT a higher rat-ing of perceived exertion, indicatrat-ing that they found it more challenging than MOD. Both concurrent training conditions were rated as substantially more challenging than resistance training alone, unsurprisingly.
Nutrition
All three groups had similar caloric intake and macronutrient profiles. Most important for our purposes here, protein intake was similar, at 1.1-1.3g/kg, which is below or at the very bottom end of the 1.3-1.8g/kg range (2) proposed to maximize muscular adaptations to resistance training.
Strength
The resistance training group gained more strength in both the leg press and the bench press than either of the concurrent training groups. However, there were only meaning-ful effect size differences for the leg press. The resistance training group gained 38.5 ±
8.5% on the leg press, versus 28.7 ± 5.3% for the HIT concurrent training group, and 27.5 ± 4.6% for the MOD concurrent train-ing group. For the bench press, the resis-tance training group gained 20.5 ± 6.2%, vs. 15.9 ± 2.6% for the HIT concurrent train-ing group and 14.8 ± 2.3% for the MOD concurrent training group.
Counter-movement jump
The improvements in all measures (peak force, peak power, peak velocity, and peak displacement) tended to favor the resistance training group over either concurrent train-ing group, but there were no statistically sig-nificant differences between groups.
1 2 3 5 6 7 6 8 7 8 9 8 7 6 5 7 8 9 8 9 10 9 11 10 9 7 120 120 120 120 120 120 130 130 130 130 130 130 140 140 140 140 140 140 150 150 150 150 150
HIT
WEEK 1 SESSION 1 2 3 2 1 2 3 3 1 2 3 4 1 2 3 5 1 2 3 6 1 2 3 7 1 2 8 No. of 2-min intervals Training intensity (% LT) 15 18 21 18 24 21 24 27 24 21 18 15 21 24 27 24 27 30 27 33 30 27 21 80 80 80 80 80 80 86.7 86.7 86.7 86.7 86.7 86.7 93.3 93.3 93.3 93.3 93.3 93.3 100 100 100 100 100MOD
Duration of continuous training (min) Training intensity (% LT)10
Hypertrophy and body composition
Lower body lean mass increased slightly more in the resistance training group (4.1 ± 2.0%) and MOD concurrent group (3.6 ± 2.4%) versus the HIT concurrent group (1.8 ± 1.6%), but the difference wasn’t sig-nificant.
Upper body lean mass and total lean mass didn’t increase to a meaningful degree in any of the groups (only 0.4-1.8% and 1.6-2.4%, respectively). None of the groups had a significant change in body fat percentages, with decreases ranging from 0.2-0.9%.
Aerobic fitness
Both concurrent training groups
experi-enced similar increases in VO2 peak (5.3 ± 2.7% for HIT, and 6.1 ± 5.0% for MOD). The MOD concurrent training group had the largest increase in lactate threshold (12.6 ± 8.0%), with similar gains seen in the resistance training (7.4 ± 9.4%) and HIT concurrent training (8.3 ± 6.5%) groups. There were no significant between-group differences.
The HIT concurrent training group was the only one that experienced an increase in peak aerobic power (8.8 ± 4.1%). The gains seen in the MOD concurrent training group (4.9 ± 4.8%) weren’t significant. There was a small, non-significant decrease in the resis-tance training group (−2.2 ± 6.5%).
50 40 30 20 10
RT RT+HIT RT+MOD RT RT+HIT RT+MOD
PERCENT
STRENGTH GAINED
LEG PRESS BENCH PRESS
38.5% ± 8.5% 20.5% ± 6.2% 28.7 ± 5.3% 15.9 ± 2.6% 27.5 ± 4.6% 14.8 ± 2.3%
STRENGTH GAINS
RT = Resistance TrainingRT + HIT = Resistance Training with High Intensity Intervals
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Interpretation
If you want to maximize rates of strength gains, your best bet is to limit cardio. The magnitude of interference effects seems to depend on the frequency (3), volume, and mode of the cardio you do (1), with lower frequencies, lower volumes, and lower im-pact forms of cardio (i.e. cycling instead of jogging or running) leading to a smaller in-terference effect. However, these measures do not negate the effect entirely.
The main finding of this study was that in-tensity of endurance training doesn’t seem to influence the interference effect if vol-ume is matched; both moderate and high intensity cardio led to similar decrements in strength gains. Since the changes in body composition in this study were small, and between-group differences were small and non-significant, it’s hard to say whether car-dio intensity would have a meaningful im-pact on hypertrophy, muscle maintenance in a calorie deficit, or overall body compo-sition in a longer-term concurrent training program.
One could contend that moderate intensity cardio came out ahead in this study for hy-pertrophy since the MOD concurrent train-ing group gained twice as much lower body lean mass as the HIT concurrent training group, but the changes were small in both groups (which makes it easier to see larg-er plarg-ercent difflarg-erences), and the difflarg-erence between groups wasn’t particularly close to statistical significance (the p-value for this particular relationship wasn’t reported, but it can be inferred to be substantially high-er than 0.05 based on what was reported). Before reaching that conclusion, I’d need to
see a longer study with a larger sample size. One other important takeaway from this study was that moderate intensity cardio seemed to be more effective per unit of ef-fort invested. Training volume (total time and workload) of endurance training was matched between the two concurrent train-ing groups, but the per-session RPE was higher for the group doing HIT. However, both groups experienced very similar adap-tations.
Finally, it’s important to keep timing in mind. In this study, the strength train-ing took place directly after the endurance training. The effects may have been different if the participants did the strength training first, if they separated their strength training and endurance training sessions by several hours, or if they performed strength train-ing and endurance traintrain-ing on different days. Doing so would likely help mitigate the interference effect on a molecular level (4), and also, on a more practical level, allow for resistance training to take place with less acute fatigue from cardiovascular training (which would be a bigger issue with HIT than MOD).
The major takeaway of this study is that if you want to maximize your rate of strength gains, you should try to avoid cardio or limit the amount you do. If you undertake concur-rent training, the intensity of the endurance training you do doesn’t seem to meaning-fully affect the magnitude of the interfer-ence effect. However, moderate intensity endurance training is less difficult per unit of training volume.
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Next Steps
To further elucidate the impact of endur-ance training intensity on the interference effect, future studies should include a low intensity group, test different populations (such as athletes with more strength train-ing experience), and experiment with the impact of timing of the endurance exercise training.
APPLICATION AND TAKEAWAYS
1. If your goal is to maximize gains in strength and muscle mass, your best bet is to limit any sort of endurance training to a bare minimum (or exclude it entirely).
2. If you need to perform endurance training, both high intensity intervals and moderate intensity aerobic exercise seem to elicit the interference effect to roughly the same degree.
3. As moderate intensity cardio was rated to be easier than high intensity intervals per unit of workload, it may be the better choice. However, feel free to use whichever mode of cardio you find to be the most enjoyable and easiest to stick with, assuming you need to do it in the first place.
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References
1. Wilson JM, Marin PJ, Rhea MR, Wilson SM, Loenneke JP, Anderson JC. Concurrent training: a meta-analysis examining interference of aerobic and resistance exercises. J Strength Cond Res. 2012 Aug;26(8):2293-307. doi: 10.1519/JSC.0b013e31823a3e2d.
2. Phillips SM, Van Loon LJ. Dietary protein for athletes: from requirements to optimum adaptation. J
Sports Sci. 2011;29 Suppl 1:S29-38. doi: 10.1080/02640414.2011.619204.
3. Jones TW, Howatson G, Russell M, French DN. Performance and Endocrine Responses to Differing Ratios of Concurrent Strength and Endurance Training. J Strength Cond Res. 2016 Mar;30(3):693-702. doi: 10.1519/JSC.0000000000001135.
4. Baar K. Using Molecular Biology to Maximize Concurrent Training. Sports Medicine (Auckland, N.z).
2014;44(Suppl 2):117-125. doi:10.1007/s40279-014-0252-0.
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Does the Configuration of
Weekly Training Session Order
Matter for Strength?
B Y M I C H A E L C . Z O U R D O S
Study Reviewed: Comparison of powerlifting performance in
trained males using traditional and flexible Daily Undulating
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aily undulating periodization(DUP), the practice of altering repetitions or training focus (hy-pertrophy, strength, or power) each session, has increased in popularity in recent years. However, when the prescribed repetition schemes are performed in a fixed order throughout the week, the resulting rigidity may not accommodate fluctuations in the athlete’s readiness, so it may be beneficial to incorporate some form of autoregulation within a DUP model. This study compared a flexible DUP (FDUP, n=14) strategy against a fixed DUP (n=11) weekly strategy to test this hypothesis with trained males. The FDUP lifters could choose which dai-ly training session they wanted to do (hy-pertrophy, strength, or power) based upon their daily readiness, with the stipulation that each of the three sessions must be per-formed within each week. The DUP group performed training in the fixed weekly order of hypertrophy (Monday), power (Wednes-day), and strength (Friday). The training programs lasted 9 weeks, and squat, bench press, and deadlift 1RMs, along with Wilks Score (relative strength) were tested before
and after the 9 weeks. Further, total volume and repetitions performed were compared between groups.
Both groups had significant increas-es (p<0.05) in both absolute and relative strength for all individual lifts and pow-erlifting total (FDUP: +9.3% and DUP: +9.2%) over the 9 weeks, but there were no differences between groups for any strength measure (p>0.05). Additionally, there were no group differences in training volume or repetitions (p>0.05). Interestingly, there was possibly slightly greater adherence to train-ing in favor of FDUP. Importantly, FDUP produced similar adaptations in trained males to a fixed weekly order DUP config-uration of hypertrophy, strength, and then power over 9 weeks.
Purpose and Research
Questions
The purpose of this study was to compare the effects of 9 weeks of DUP versus FDUP (i.e. flexible order of weekly training ses-sions) training on training volume and
ab-D
KEY POINTS
1. This study compared a fixed weekly order of daily undulating periodization training versus a program in which weekly training order was flexible based upon a lifter’s readiness.
2. Both groups had significant increases in squat, bench press, and deadlift strength over 9 weeks of training, with no significant differences between groups.
3. Despite no strength differences, a flexible weekly order may increase adherence. 4. Lifters in the present study were fairly well-trained, which makes these findings
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solute and relative strength in the powerliftsand powerlifting total. A secondary aim was to assess if there were any differences be-tween satisfaction of training sessions, rat-ing of perceived exertion (RPE) per session, or motivation to train when using a flexible versus a fixed weekly training order.
Research question 1: Does a flexible
week-ly training order (FDUP) result in greater strength and total volume performed than a fixed weekly training order (DUP)?
Research question 2: Does FDUP result in
greater motivation to train and training sat-isfaction than DUP due to allowing indi-viduals to choose workouts based upon daily readiness and desire?
The authors hypothesized: 1.) That FDUP would result in greater strength ad-aptations (absolute and relative) compared to DUP due to greater readiness allowing for more repetitions performed, thus more total volume; and 2.) Subjects would have higher motivation to train and greater satis-faction with a training session with FDUP compared to DUP.
Clarity note
These hypotheses are based on the con-cept that autoregulating training sessions based upon daily readiness would improve performance.
Subjects and Methods
Subjects
Subjects were 34 males with at least 6 months of training three times per week and 1RMs of at least the following:
• Back squat: 1.25 times body mass
(BM).
• Bench press: 1 times BM. • Deadlift: 1.5 times BM.
However, only 25 subjects completed the study (FDUP: n=14, DUP, n=11).
This is about a 16% dropout rate, for var-ious reasons, which is not uncommon in a training study. 25 finishing subjects is a pretty good sample size in comparison to similar research (2).
For 9 weeks, each group trained on three non-consecutive days per week. DUP trained in the weekly order of hypertrophy, pow-er, and then strength. FDUP could choose which session they wanted to perform upon entering the laboratory with the stipulation that all session types must be performed each week; therefore, each group would be performing one hypertrophy, one power, and one strength session per week, albeit in a potentially different configuration. At pre- and post-testing, there were 1RM tests for the powerlifts along with body composition assessment via ultrasound.
Further, session RPE was assessed follow-ing each trainfollow-ing session to gauge a mea-sure of overall post-training fatigue, while motivation to train and training satisfaction were gathered before and after each session, respectively.
Training program
The specifics of the training program can be seen in Table 1.
The only difference between groups was the ability of the FDUP group to choose the weekly training order. Squat and bench press were performed every session, while deadlift was only performed during power sessions.
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HYPERTROPHY DAY Week
1 Weeks 2-3 Weeks 4-6 Weeks 7-8 Week9
Squat Bench press 4×8+ @70% 4×8+ * 4×6+ * 4×5+ * 2×5+ * 4×8+ @70% 4×8+ * 4×6+ * 4×5+ * 2×5+ * STRENGTH DAY Week
1 Weeks 2 and 3 Weeks 4-6 Weeks 7-8 Week9
Squat Bench press Deadlift 4×3+ @85% 4×3+ ** 4×2+ ** 4×1+ ** 2×1+ ** 4×3+ @85% 4×3+ ** 4×2+ ** 4×2+ ** 4×1+ ** 4×1+ ** 2×1+ ** 2×1+ ** 4×3+ @85% 4×3+ ** POWER DAY Week
1 Weeks 2 and 3 Weeks 4-6 Weeks 7-8 Week9
Squat Bench press Deadlift 6×1 @80% 6×1 @80% 6×1 @80% 6×1 @80%P1RM 6×1 @80% P1RM 6×1 @85%P1RM 4×1 @90%P1RM 2×1 @90%P1RM 2×1 @90% P1RM 4×1 @90% P1RM 6×1 @85% P1RM 6×1 @80% P1RM 6×1 @85%P1RM 4×1 90%P1RM 2×1 @90%P1RM
TABLE 1: TRAINING PROGRAM
This table displays the training program for the main lifts for the entire study. All notations are “Sets×Reps”. For the power day, percentages of one-repetition max-imum (1RM) after week 1 were based upon a predicted 1RM, which was calcu-lated via the Epley Formula using the previous week’s plus set performance on the strength day. Pre-testing was completed 48-72 hours prior to the first training session, and post-testing occurred 48-72 hours following the last session in week 9. Additionally, assistance exercises: (DB lateral raise, DB triceps extension, DB curl for hypertrophy day; pullups and abs for power day; and barbell row and abs for strength day) were performed with either 3×12 or 3×15 in week 1 and decreased to either 2×6 or 2×8 in week 9.
+Plus set= As many repetitions as possible were completed on the last set of this exercise.
*Hypertrophy day progressed based upon plus set repetitions in accordance with Table 2.
** Strength day progressed based upon plus set repetitions in accordance with Ta-ble 2.
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Load progression
For progression, a plus set (as many repe-titions as possible) was implemented on hy-pertrophy and strength sessions, and loads were autoregulated for the following week on that session based upon plus set perfor-mance (Table 2). Additionally, 2-3 assis-tance exercises were performed each session in the exact same manner for each group to avoid subjects doing additional training outside of the laboratory.
Findings
All strength measures increased; however, there were no statistically significant differ-ences between groups for any measure.
Training volume, repetitions completed, and average training intensity
Both groups did roughly the same num-ber of reps on their plus sets, and volume through the rest of the training week was equated. Therefore, there were no significant group differences (p>0.05) in training vol-ume or total reps performed.
PLUS SET REPETITIONS
WEEKLY LOAD ADJUSTMENT
5 reps or fewer under goal Decrease 7.5kg for next week session-type 3-4 reps under goal Decrease 5kg for next week session-type 1-2 reps under goal Decrease 2.5kg for next week session-type 0-1 reps under goal Same load for next week session-type 2-3 reps above goal Increase 2.5kg for next week session-type 4-5 reps above goal Increase 5kg for next week session-type 6 reps or more above goal Increase 7.5kg for next week session-type
T A B L E 2 : W E E K L Y L O A D
P R O G R E S S I O N C H A R T
Adjustments are referring to the same session type for the following week. For example, if 5 more repetitions than required were completed on the strength session in week 2, then 7.5kg would be added for the strength session in week 3. Adapted from Colquhoun et al. (1)
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Further, since progression wasautoregu-lated, average intensity could be calculated. There was no difference (p>0.05) between groups for average intensity, suggesting that rate of progression was similar between groups. In fact, average intensity through-out the 9 weeks was very similar for squat (DUP: 87% and FDUP: 86% of 1RM), bench press (DUP: 86% and FDUP: 87% of 1RM), and deadlift (DUP: 87% and FDUP: 83% of 1RM).
Strength
As previously stated, all strength measures increased from pre- to post-testing, but no differences existed between groups (Table 3). Furthermore, an effect size was calculat-ed for each group from pre- to post-testing to examine the magnitude of change. No ef-fect sizes were drastically different between groups, indicating that the meaningful mag-nitude of change was also similar.
Research understanding note: The
calculat-ed pre-to-post effect size for both groups is not a direct comparison; rather, it is a mag-nitude inference for each individual group. However, effect sizes can also be calculat-ed in a manner which allows you to com-pare the groups directly, which may be more helpful than simply calculating pre-to-post effect sizes for each group (3).
Research applicability note: The absolute
values for squat, bench press, and deadlift 1RM are presented in Table 3 to show the training status of the individuals. While an average ending deadlift of >180kg in each group (about 400lbs) and squat of 165kg (363lbs) in DUP is not overly impressive to most readers of MASS, this is actually quite good for resistance training research, which
makes these findings more applicable than most for a competitive strength sport pop-ulation.
Perceptual measures
All perceptual measures (motivation to train, training session satisfaction, and ses-sion RPE) were similar between groups. FDUP did not provide an additional psy-chological benefit compared to the DUP weekly training order of hypertrophy, power, and strength.
Body composition
There were no changes from pre- to post-testing, nor were there any differences between groups for any of the body compo-sition measures (fat-free mass, fat mass, or body fat percentage). No change here should have been expected, as this was not the point of the study, nor was dietary intake tracked. As a side note, just to give greater insight into the population, body fat percentage was about 11% in FDUP and 13% in DUP for males who weighed 80kg on average.
Interpretation
This study reported no significant dif-ferences in strength gains between groups; therefore, allowing flexibility in weekly session configuration using DUP did not enhance adaptations compared to a fixed session order. Correspondingly, the average number of repetition across all plus-set days was almost identical (FDUP: 9 versus DUP: 8), meaning there were no group differences in training volume.
Previously McNamara and Stearne (2010) reported that a flexible non-linear
20
tion model produced greater strength gainsthan an inflexible non-linear approach (4) in a 12-week program that allowed subjects to choose between a 20-, 15-, or 10-repeti-tion day over two weekly training sessions. However, subjects in that study only had the stipulation that they had to complete each training type eight times (1/3 of the 24 to-tal sessions) over the 12 weeks, whereas the presently reviewed study from Colquhoun and colleagues restrained subjects to only allowing within-week flexibility (i.e. hy-pertrophy, strength, and power all had to be performed within the same week). Because there was less flexibility in Colquhoun’s study, there was an increased chance of an
individual training with low readiness, pos-sibly resulting in the conflicting results.
As a side note, these two studies used dif-ferent terminology: flexible daily undulating periodization versus flexible non-linear pe-riodization. While both are correct, non-lin-ear can refer to weekly or daily undulating; thus, daily undulating is more specific and is an easier term to visualize for the reader (I prefer Colquhoun’s terminology).
This study was also modeled after Zour-dos et al. (2016), and the present results also differed slightly in this comparison. Zourdos and colleagues (2) compared two fixed weekly session configurations of DUP in powerlifters: 1.) Hypertrophy, power, FDUP
MEASURE DUP
PRE POST CHANGE% PRE POST CHANGE%
Squat 1RM (kg) Bench 1RM (kg) Deadlift 1RM (kg) 132.4 ± 34.2 95.8 ± 20.1 166.2 ± 40.6 181 ± 37.1 102.3 ± 18.8 148.0 ± 32.8 +11.8% +6.8% +8.9% 137.2 ± 30.7 118.0 ± 20.8 174.3 ± 25.4 187.9 ± 29.2 126.8 ± 21.2 165.2 ± 25.4 +12.2% +7.5% +7.8%
T A B L E 3 : P R E - T O - P O S T S T R E N G T H
C H A N G E S I N E A C H G R O U P
Powerlifting Total= Sum of squat, bench press, and deadlift. All pre- to post-testing changes are statistically significant; however, no group differences existed for any measure. Adapted from Colquhoun et al. (1)
21
and then strength (HPS – the sameor-der as Colquhoun’s fixed group) versus 2.) Hypertrophy, strength, and then power (HSP). HPS was designed to manage fa-tigue (separating the strength session from the hypertrophy session, which was likely to cause the most muscle damage), and it led to larger strength gains than HSP, as hypothesized (2). Colquhoun then adapt-ed the already-successful HPS configura-tion and compared it to FDUP. Ultimately, FDUP may have not been more favorable in the presently reviewed study because the comparison model (HPS) already has fa-tigue and readiness management built into the configuration (i.e. separating strength 96 hours from the most damaging week-ly session: hypertrophy). However, none of the above is to say that an FDUP strategy is not useful or never has its place. As with any finding, we cannot look at results in a vacuum; we must learn to think conceptu-ally. Below, I want to present two ways of how understanding conceptually can allow you to utilize a flexible template:
1). When looking further into these re-sults, we see that overall adherence to train-ing may have been slightly better in FDUP. Specifically, both groups started with 16 subjects, for a total of 32 subjects (34 total were screened, but 2 did not meet the in-clusion criteria). All 16 finished the FDUP protocol, while only 11 finished the DUP protocol. At the end, data from only 14 sub-jects were used for FDUP (as 2 were ex-cluded for engaging in exercise outside of the study). Furthermore, 79% of the subjects in the FDUP group completed every train-ing session, while 73% of the subjects in the DUP group completed every training
ses-sion. It may be that allowing within-week flexibility increased adherence, despite not producing differences in the motivation to train on the Likert scale. Adherence is ob-viously one of the most important factors when designing a training program. If an individual does not adhere to the training prescription, everything else is of trivial im-portance. Thus, some flexibility may be ben-eficial in the long-term.
2). Second, utilizing a “somewhat flexible” weekly configuration may be beneficial. This recommendation takes into account that the already-established weekly order of HPS is beneficial, but fluctuations in daily readiness do happen, and long-term increased ad-herence should still play a role in program design. Therefore, it seems logical that you could train with a pre-determined order of HPS while reserving the right to still im-plement a flexible strategy in extreme sit-uations (i.e. < 4 hours sleep or less than 30 minutes of availability to train). To accom-plish this, we must think outside of the box.
Even though one hypertrophy, one power, and one strength day were performed within each study by both Colquhoun and Zourdos, if a “somewhat” flexible model (Table 4) is used, the HPS order could be implemented with the freedom to add a power day (since power-type sessions are the least taxing and consume the least amount of time) in the situations mentioned above, then continue on with the next day that had already been scheduled before the power day was "flexed" in. In essence, this would not control for number of session types within each week; it would simply allow a power-type session to be substituted when readiness or time stipulations occur. If preferred, session-type
22
stipulations could be given in the long-term(i.e. over months). Two examples of “some-what” flexible strategies can be seen in Table 4 compared to the fixed HPS.
It should also be noted that this study provides an example of an integrated peri-odization strategy (this can be seen in the methods). Specifically, although DUP was used within each week, the methods de-scribe how repetitions on the hypertrophy- and strength-type days decreased every few weeks, thus causing an increase in
intensi-ty in an effort to peak. This design shows a within-week DUP strategy encompassed with overall linear changes. I am sure MASS will cover this concept in more detail at some point, but this is an excellent example of how to look beyond the presented data to see the intricate details of a study design. The design demonstrates that these authors possess a solid understanding of scientific and practical program design.
WEEK 1
WEEK DAY
WEEK 2
MON. WED. FRI. MON. WED. FRI.
FIXED: HPS (Zourdos / Colquhoun) Somewhat flexible, example 2
H
P
S
S
P
H
H
P
S
Somewhat flexible, example 1H
P
P
S
H
P
P
H
P
T A B L E 4 : P R O P O S A L O F S O M E W H A T
F L E X I B L E T R A I N I N G M O D E L S
In the proposed model, the last two rows present a “somewhat flexible” weekly configuration. In example 1, the lifter sets out with a normal HPS (hypertrophy, power, and strength) weekly training order; however, the individual can “flex” in a power day when necessary without al-tering the overall pattern. Thus, after the extra power day is inserted in week 1 due to poor readiness (fatigue, sleep disruption, etc.), the individual simply keeps the planned order and picks up with strength in the following session. In example 2, the individual "flexes" in a power day as needed on Monday of week 2 and then simply picks up with hypertrophy-type training in the next session, which would otherwise have been performed on Monday.
23
Next Steps
Ultimately, the flexible strategy imple-mented was not more effective than the fixed HPS order; however, this is not to say that flexible templates have no benefit (as discussed above). It is important to imple-ment a flexible strategy over the long term in future studies to examine if adherence is truly increased. If adherence is indeed in-creased in the long term, this would be solid evidence for allowing a “somewhat” flexi-ble strategy within your program design to avoid having a high intensity session when readiness to train is poor.
APPLICATION AND TAKEAWAYS
1. Within-week flexibility of session order when using hypertrophy-, power- and strength-type sessions did not allow for higher training volumes or produce larger strength gains than a fixed weekly order of HPS.
2. The flexible DUP model did perhaps provide a slight increase in adherence to training. 3. If using DUP, it may be beneficial to utilize a weekly order of HPS but allow for some
flexibility to increase adherence and maximize daily readiness on high intensity days. 4. An integrated periodized approach – which fluctuates number of repetitions within the
week, yet still decreases volume and increases intensity over time – is a beneficial and practical approach to programming.
24
References
1. Colquhoun, RJ, Gai, CM, Walters, J., Brannon, A., Kilpatrick, MW., D’Agostino, DP, Campbell, BI. Comparison of Powerlifting Performance in Trained Men Using Traditional and Flexible Daily Un-dulating Periodization. The Journal of Strength & Conditioning Research. [Epub Ahead of Print] 2. Zourdos MC, Jo E, Khamoui AV, Lee SR, Park BS, Ormsbee MJ, Panton LB, Contreras RJ, Kim JS.
Modified daily undulating periodization model produces greater performance than a traditional configu-ration in powerlifters. The Journal of Strength & Conditioning Research. 2016 Mar 1;30(3):784-91. 3. Dankel SJ, Mouser JG, Mattocks KT, Counts BR, Jessee MB, Buckner SL, Loprinzi PD, Loenneke
JP. The widespread misuse of effect sizes. Journal of Science and Medicine in Sport. 2016 Oct 19. 4. McNamara JM, Stearne DJ. Flexible nonlinear periodization in a beginner college weight
train-ing class. The Journal of strength & conditioning research. 2010 Aug 1;24(8):2012-7.
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B Y E R I C H E L M S
Study Reviewed: Resistance training-induced changes in
integrated myofibrillar protein synthesis are related to
hypertrophy only after attenuation of muscle damage.
Damas et al. (2016)
o better understand how muscle growth occurs in response to weight training, 10 young males performed
the leg press and leg extension twice per week for 10 weeks. Very small portions (100 mg) of thigh muscle were surgically removed
T
Is Muscle Damage
Related to Hypertrophy?
26
(a biopsy) immediately before, 1 day and 2days after the first training session, during a session in week 3, and at the last training session in week 10. Individual muscle fiber cross-sectional area, the rate that new teins were added to the muscle (muscle pro-tein synthesis - MPS), and the damage to the muscle from training were determined from these biopsies.
Muscle fiber growth was measurable by week 10. Muscle damage was the highest after the initial training session, lower by week 3, and the lowest at week 10. MPS was highest after the initial session, and lower by week 3, which remained the same at week 10. Fiber growth had a very strong relationship with MPS at week 3 and 10 but had no relationship with MPS after the first training session. Thus, MPS in the earliest
stage of resistance training is not primari-ly directed toward muscle growth. Muscle growth and MPS are only strongly related once muscle damage decreases.
Purpose and Research
Questions
The researchers wanted to know at what time point MPS becomes predictive of hy-pertrophy. They hypothesized that the ini-tial rise in MPS in response to resistance training would be higher than at later time points and that this would be due to mus-cle damage. Additionally, they hypothesized that muscle damage would be the highest after the initial training bout and would decrease over time. Finally, they speculated
KEY POINTS
1. Initial muscle protein synthesis response to resistance training (within ~48 hours) is not predictive of long-term hypertrophy when muscle damage is high (due to unfamiliar movements, untrained participants, or eccentric training). Rather than muscle protein synthesis being driven toward hypertrophy, the initial elevation is driven by muscle damage repair.
2. Conclusions about the muscle growth potential of nutrition or training protocols cannot be made based on muscle protein synthesis data when substantial muscle damage is present.
3. Muscle protein synthesis after multiple weeks of training, after the repeated bout effect has dampened muscle damage, is highly predictive of hypertrophy.
4. Muscle damage was not correlated with hypertrophy in this study. Additionally, high levels of muscle damage (such as when training for the first time, or after an extended lay off, or when training a muscle group for the first time) reduces strength by more than 20% for at least 48 hours. Thus, muscle damage likely should not be purposefully sought out in training. Additionally, a gradual increase in volume and intensity is advised to reduce the damage response in order to manage fatigue and promote faster strength gains.
27
that MPS would not be related tohyper-trophy initially [as was shown by a previous study from this lab (1)], but would by week 3 and 10, after muscle damage decreased.
Subjects and Methods
10 more-or-less untrained young men participated in this study; they hadn’t per-formed lower body training for 6 months, but had previous experience with it (this in-dicates the participants had participated in this lab’s research before but did not regu-larly lift weights).
The methods used in this study are a big reason why the findings are important. This was a long-term study measuring MPS at multiple time points over 10 weeks.
The majority of prior research in this area consists of short-term studies done post-ex-ercise and lasting ~6-12 hours, in which chemically labeled amino-acids are infused via catheters and traced to determine the rate at which they are incorporated into muscle.
Unlike prior research, in this study, the in-vestigators had the participants drink deu-terium oxide (heavy water; ²H2O) and mea-sured the “deuterated” amino acids that had been incorporated into the muscle samples. Additionally, they took indirect measure-ments of muscle damage: subjective ratings of soreness on a 1-100 scale, creatine kinase (a blood marker of muscle damage), and maximum isometric voluntary contractile strength (this tends to decline when damage is high). They also directly assessed muscle damage by microscopically viewing z-band streaming (the mechanical disruption of the
actin-myosin cross bridges) in the biopsies.
Findings
The highest MPS occurred 24 hours after the initial training session, and this dropped slightly at the 48-hour mark. Integrated (0-48 hours post-exercise combined) MPS was higher after the initial exercise session than after sessions in week 3 or 10, which were similar to one another. At all time points (initial and weeks 3 and 10), MPS was higher 24 hours post-exercise than 48 hours post-exercise. Interestingly, when the MPS specifically related to damage was corrected for (using the formulae: MPS × (100 − fi-ber area where Z-band streaming was pres-ent)/100), MPS was not different between weeks 1, 3, and 10.
Soreness peaked 48 hours after the ini-tial exercise bout (61/100), and the second highest soreness rating was 24 hours after the initial bout (40/100). In weeks 3 and 10, soreness remained very low at all time points (0-10/100). Creatine kinase levels in week 1 were the highest, and they dropped by ~50% by week 3, and then dropped again by 50%
HYPERTROPHY HAD NO
RELATIONSHIP WITH ANY
MARKER OF MUSCLE DAMAGE,
DIRECT OR INDIRECT,
28
in week 10, relative to week 3. Maximumvoluntary contractile strength decreased ~22% 24-48 hours after the initial training session, and then only by 2-6% 24-48 hours after sessions in weeks 3 and 10. Direct measurement of z-band streaming showed the highest muscle damage after the first training session, decreasing dramatically by weeks 3 and 10.
Fiber hypertrophy of ~14% was measur-ably different relative to baseline by week 10. Hypertrophy had no relationship with any marker of muscle damage, direct or in-direct, at any time point. Furthermore, hy-pertrophy had no relationship with MPS after the initial training bout. However, fi-ber hypertrophy had a strong relationship (r = 0.91) with integrated MPS at week 10. Whole muscle cross sectional area shown in a different study using the same participants
(3) also had no relationship after the ini-tial exercise bout and a strong relationship with integrated MPS at weeks 3 (r = 0.86) and 10 (r = 0.95); this means that MPS can explain 74-90% of the variation in muscle growth if it's measured once muscle damage
has subsided. Interestingly, initial post-ex-ercise MPS had a moderate and near-ly significant relationship with the direct measure of muscle damage 48 hours after the first training bout (r = 0.56, p = 0.09).
Interpretation
This study is groundbreaking for sever-al reasons. First, it had long been assumed that MPS was a surrogate measurement for hypertrophy. This was not questioned until the now-famous Schoenfeld, Aragon, and Krieger meta-analysis of post workout protein consumption found, at best, a weak relationship between post-workout protein consumption and hypertrophy, which con-trasted starkly with MPS data (4). The sec-ond blow to the value of MPS data came in the form of a 16-week training study that found no relationship between MPS after the first session and hypertrophy (1). This study came directly from Stu Phillips’ lab, where the most well-known research in this area is conducted. At the time, it was not known why there was no relationship, but this study explains why. Now, we know that initial MPS is likely driven by damage re-pair, not muscle growth. This discovery was only possible because of the new methods used to measure MPS employed in this study, which allow collections to occur over weeks versus hours.
However, an interesting side effect of this study is that it draws into question the as-sumptions made about hypertrophic-poten-tial in prior research using short-term MPS methods. It is possible that many of the pre-vious short-term MPS studies that utilized untrained participants, or unfamiliar
move-STRENGTH IS ACUTELY
DECREASED BY MUSCLE DAMAGE,
WHICH DECREASES YOUR ABILITY
TO PRODUCE PROGRESSIVE
29
ments, were in large part capturing thedam-age response rather than MPS directed at muscle growth. Based on the data presented in this study, MPS can only be assumed to relate to hypertrophy in short-term studies if participants with prior resistance train-ing experience performed movements with which they were familiar that were not ec-centrically biased [eccentric contractions cause the most muscle damage (5)]
Additionally, this study serves as an in-structive tool for the repeated bout effect. The repeated bout effect is a phenomenon in which the muscle is protected against damage from future muscular work when it performs repeated bouts of a similar task (6). As demonstrated in this study, both di-rect and indidi-rect markers of muscle damage decreased by weeks 3 and 10 of training. Interestingly, there has been considerable debate as to the role of muscle damage in hypertrophy, with some stating it is a mech-anism influencing muscle growth (7), while others claim that it occurs during muscu-lar work but is not causative (8). Thus, there is understandable confusion as to whether the repeated bout effect is a “good or bad” thing. Indeed, if muscle damage is a criti-cal component to hypertrophy, then efforts should be employed to ensure muscle dam-age continues and the repeated bout effect is avoided (i.e. changing exercises, purposeful detraining, etc). However, if muscle dam-age is not a critical component to hyper-trophy, efforts should be employed to elicit the repeated bout effect. As shown in this study, strength is acutely decreased by mus-cle damage, which decreases your ability to produce progressive overload.
While this study doesn’t definitively
an-swer whether muscle damage is “good or bad,” it does show that muscle damage is not related to hypertrophy. However, we can’t conclude from this study that muscle dam-age has a directly negative effect on hyper-trophy, as it appears that MPS, when it was corrected for damage, was very similar at all three points. If damage was actually having a directly negative effect on muscle growth (i.e. the drive to repair muscle was taking away from the drive to build it), you would expect to see damage-corrected MPS at its lowest after the first session when damage was highest. At worst, you could conclude from this study that damage could have an indirectly negative effect on muscular ad-aptation. Strength was decreased by ~22% for 48 hours (and perhaps longer) after the initial bout. However, after the repeated bout effect was in place, strength was only decreased by 2-6% in the 48 hours after the bouts in weeks 3 and 10.
As a strength athlete, a large part of per-formance improvement comes down to managing the fatigue generated by training. Thus, efforts should be made to acclimate your body to the workload you are attempt-ing to achieve in trainattempt-ing. Introductory me-socycles where load, stress per set (RPE), and volume are purposely low are an ex-cellent method of starting a training block. Additionally, increasing volume in a grad-ual, incremental manner over a career also serves to acclimate you to higher workloads in a macroscopic sense.
Next Steps
While this study suggests a lack of rela-tionship between hypertrophy and muscle
30
damage, it is important to point out thatthis is a single group, correlational analysis of two variables within this group. To truly answer the riddle of whether muscle dam-age has an additive, causative, or negative role in hypertrophy, future research needs to compare two groups in which volume and intensity are matched, yet greater damage is elicited in one group. This is certainly not an easy task and would likely require eccentri-cally biasing the training of one group while maintaining matched volume and intensi-ty. However, despite the difficult design, it would be necessary to finally answer this question.
APPLICATION AND TAKEAWAYS
1. Short-term studies examining MPS using untrained subjects, unfamiliar movements, or assessing subjects after a detraining period may not be predictive of long-term hypertrophy due to the elevations in MPS being driven by damage rather than hypertrophy.
2. The “hypertrophic potential” of a study protocol can only be accurately assessed after damage has subsided due to the repeated bout effect.
3. The repeated bout effect protects against the suppression of strength caused by muscle damage. Jumping into a high-volume or high-intensity training approach, relative to what you were previously doing, can circumvent progress due to degradation of strength from excessive muscle damage. Combine this with the lack of a relationship between hypertrophy and damage, and we can conclude that we should not purposefully seek out muscle damage in training.
4. To avoid the detrimental effects of excessive muscle damage, gradually acclimate yourself to higher levels of volume and intensity as needed to progress, in an incremental fashion.
31
References
1. Mitchell CJ, Churchward-Venne TA, Parise G, Bellamy L, Baker SK, Smith K, Atherton PJ, and Phillips SM. Acute post-exercise myofibrillar protein synthesis is not correlated with resistance train-ing-induced muscle hypertrophy in young men. PloS one 9: e89431, 2014.
2. Barrett EJ, Revkin JH, Young LH, Zaret BL, Jacob R, and Gelfand RA. An isotopic method for mea-surement of muscle protein synthesis and degradation in vivo. Biochemical Journal 245: 223-228, 1987. 3. Damas F, Phillips SM, Lixandrão ME, Vechin FC, Libardi CA, Roschel H, Tricoli V, Ugrinowitsch
C. Early resistance training-induced increases in muscle cross-sectional area are concomitant with ede-ma-induced muscle swelling. Eur J Appl Physiol 116: 49-56, 2016.
4. Schoenfeld BJ, Aragon AA, and Krieger JW. The effect of protein timing on muscle strength and hyper-trophy: a meta-analysis. Journal of the International Society of Sports Nutrition 10: 53, 2013. 5. Proske U and Morgan DL. Muscle damage from eccentric exercise: mechanism, mechanical signs,
adap-tation and clinical applications. J Physiol 537: 333-345, 2001.
6. Zourdos MC, Henning PC, Jo E, Khamoui AV, Lee SR, Park YM, Naimo M, Panton LB, Nosaka K, and Kim JS. Repeated Bout Effect in Muscle-Specific Exercise Variations. Journal of strength and conditioning research 29: 2270-2276, 2015.
7. Schoenfeld BJ. The mechanisms of muscle hypertrophy and their application to resistance training. Journal of strength and conditioning research 24: 2857-2872, 2010.
8. Flann KL, LaStayo PC, McClain DA, Hazel M, and Lindstedt SL. Muscle damage and mus-cle remodeling: no pain, no gain? The Journal of experimental biology 214: 674-679, 2011.
32
When the Whole is Less
Than the Sum of its Parts
B Y G R E G N U C K O L S
Study Reviewed: Bilateral deficit in maximal force
production. Škarabot et al. (2016)
he bilateral deficit is a simple concept: If you do a one-rep max for both limbs using a unilateral exercise, then add up those two lifts, the result will generally be greater than your one-rep max for a bilateral version of the same exercise. For example, if
you do a one-rep max unilateral knee exten-sion (which is used in much of the research), and you can move 65kg with your dominant leg and 60kg with your non-dominant leg, your one-rep max knee extension when us-ing both legs will probably be a bit less than
33
125kg.The bilateral deficit has been observed in many contexts, including exercises ranging from knee extensions to gripping to fin-ger adduction, and including concentric, eccentric, isometric, and even explosive movements. This review set out to identify the magnitude of the bilateral deficit and to evaluate several hypotheses that have been used in an attempt to explain why it occurs.
Purpose and Research
Questions
The bilateral deficit was first noted by the researchers Henry and Smith in 1961. Since then, dozens of studies have investi-gated the effect, employing a wide array of research designs. The last thorough review (1) of the phenomenon was from 2001, so the authors of this review sought to give an
updated picture of the state of the research. The authors set out to determine if the bilateral deficit depended on the type of contraction or type of movement and to tease out the underlying mechanisms ex-plaining the bilateral deficit. Finally, they wanted to see if the bilateral deficit was re-lated to athletic performance or injury risk.
Subjects and Methods
As this was a review paper, subjects in-volved in the studies that were reviewed run the gamut of age, sex, and experience level. The studies reviewed used a wide va-riety of protocols to measure the bilateral deficit, including maximal isometric and dynamic contractions, and explosive move-ments such as counter-movement jumps. Importantly, all of the studies employed maximal contractions of some sort.
KEY POINTS
1. Generally, people are capable of producing a bit less than twice as much force bilaterally as unilaterally. For example, if you added up your 1RM dumbbell preacher curls with both arms, the resultant weight would likely be a bit more than you could preacher curl with a barbell using both arms at the same time. This is known as the bilateral deficit. 2. For measures of maximal force, the bilateral deficit tends to be around 10%.
3. For measures of explosive force, the bilateral deficit tends to be considerably larger. 4. Many mechanisms have been proposed to explain the bilateral deficit. Several of the
more likely mechanisms are discussed in this article.
5. The bilateral deficit is affected by training. When people train unilaterally, the bilateral deficit tends to get larger, and when people train bilaterally, the bilateral deficit tends to get smaller. In fact, a few studies actually show bilateral facilitation can occur, where the sum of maximal unilateral forces is lower than maximal bilateral force.
34
Findings
Magnitude of the bilateral deficit
For dynamic (not explosive) contractions, the bilateral deficit averaged 5.8±3.5% for the upper body and 13.2±10.3% for the low-er body. For isometric contractions, the bi-lateral deficit averaged 9.0±8.0% for the up-per body and 8.1±9.2% for the lower body. The average bilateral deficit tended to be somewhat larger for explosive movements, but the measurements were too heteroge-neous (rate of force development, power,
jump height, etc.) to make a simple average meaningful.
Likely mechanisms for the bilateral deficit
The researchers identified 13 potential mechanisms for the bilateral deficit that have been proposed in previous studies. Many were deemed to be unlikely (or in-credibly minor) contributors, but they iden-tified several factors that do likely contribute to the bilateral deficit.
1.) Task familiarity: Most of your
move-ments in day-to-day life are reciprocal (each
0 -5 -10 -15 -20 -25 UPPER
BODY LOWERBODY AVERAGE
DYNAMIC
CONTRACTION CONTRACTIONISOMETRIC
UPPER
BODY LOWERBODY AVERAGE
M A G N I T U D E O F T H E
B I L A T E R A L D E F I C I T
35
side of the body doing different thingsinde-pendently). The simplest example is walking – one leg is planted on the ground while the other swings forward. You don’t hop on both legs like a kangaroo for locomotion. With that in mind, it would make sense that when exposed to a new movement, people would naturally be better at using one limb at a time instead of using both simultaneous-ly. In fact, research has shown (2) that the magnitude of the bilateral deficit decreases as familiarity with a task increases, lending support to this idea. It may be that you’re not inherently stronger using one side of your body at a time, but rather that using one side of your body at a time is just what comes the most naturally before you learn the bilateral version of a movement.
2.) Postural stability and the use of
counter-balances: If you’ve ever done unilateral knee
extensions, I’m sure you know what position your body winds up in when you’re trying to eek out the last couple of reps. You lean away from the leg you’re using, and squeeze down on the handle of the machine with your op-posite hand; you may not be entirely sure why you do it, but you know it lets you grind out another rep or two. The same thing can happen in the lab. When people are tested on a dynamometer that allows for leaning and twisting of the trunk, the bilateral defi-cit shows up. When you take measures to ensure a neutral posture, the bilateral deficit decreases or disappears. This distinction was only made in the literature (3) 13 months ago, so future studies may discover the bilat-eral deficit is either smaller or nonexistent as methodology gets more rigorous. On the other hand, in a “real world” scenario (i.e. if you’re worried about applicability of this
concept outside of a lab setting), you can contort your body and brace in ways to gain an advantage with unilateral tasks that aren’t available with bilateral tasks. In other words, even if the actual maximal force of muscle contraction isn’t different with unilateral versus bilateral tasks, that doesn’t necessari-ly mean performance in unilateral exercises won’t be more than half the performance of bilateral exercises in less controlled condi-tions.
3.) Force-velocity relationship: This factor
applies to the bilateral deficit observed in explosive movements. Power is calculated by multiplying force × velocity. If the re-quired force output is too high so that ve-locity is very low (i.e. like a one-rep max deadlift), you can’t maximize power output. Similarly, if velocity is too high (i.e. trying to throw a Wiffle ball), then force output will be too low to maximize power output. Power output is maximized when attempt-ing to apply maximal force to intermediate “loads.” In this case, for something like a counter-movement jump, your bodyweight is a very light load when jumping off of two legs, but a more intermediate load when jumping off one leg; thus, you can achieve higher power output (per leg) with
unilat-POWER OUTPUT IS MAXIMIZED
WHEN ATTEMPTING TO
APPLY MAXIMAL FORCE TO
INTERMEDIATE “LOADS.”
36
eral jumps versus bilateral jumps. This sameconcept applies to measures of explosive strength using other experimental models as well. For example, one study (4) examining combined knee and hip extension on a dy-namometer found that the bilateral deficit increased linearly from 9% with isometric contractions, up to 49% with very fast con-tractions (424°/s).
4.) Neural factors: I won’t belabor the
de-tails here because, quite frankly, they’re in-teresting if you’re a neurophysiology geek, but they aren’t overly relevant for athletes or coaches. In short, there may be differences in how well you can activate your muscles due to feedback at the level of the spinal cord, and potentially interference at the level of the brain. We know that spinal reflexes can modulate force output, and they seem to be
“tuned” in favor of reciprocal movements (like walking or running). Additionally, the signals for muscle contractions in the brain have to cross between the hemispheres of the brain before making their way to your spine and eventually your muscles, so it’s possible that when you send those signals from both sides of your brain simultaneous-ly, they interfere with each other to some degree. Thus far, the experimental evidence hints that these factors may contribute, but the results are still pretty murky.
Injury risk and performance
It has been proposed (5) that since most athletic movements are unilateral or re-ciprocal, the bulk of the strength training that athletes do should be unilateral (which would increase the bilateral deficit). Howev-er, the only study (6) examining the impact
LOAD OR FORCE VELOCITY OF SHOR TENING BILATERAL POWER BILATERAL F-V CURVE UNILATERAL F-V CURVE UNILATERAL POWER UNILATERAL JUMP (PER LEG) BILATERAL JUMP
